Taking on the hardest optional boss in God of War is tough. Beating Sigrun, the final Valkyrie, demands concentration, know-how, and patience even when you've got Kratos kitted out with all of his endgame upgrades -- but what if you had to fight her with no upgrades whatsoever?

That's what YouTuber GBG did -- and he actually won. Four hours and 35 minutes into the above video, GBG goes toe-to-toe with Sigrun after multiple failed attempts and finally puts her down. The fight lasts almost 20 minutes, with Kratos' attacks barely dealing any damage. In stark contrast, a single hit is enough to end GBG's run.

Quite frankly, it's an insane battle. The dodging and weaving that GBG displays is pretty mind-blowing at times, and the fight makes for a real spectacle. You can practically feel the pressure building as Sigrun's health starts to run low.

Amazing stuff.

[source youtube.com, via reddit.com]